These units allow standard models to be upgraded to permit free access when required. The manual hold-open function is operated by a key and holds all latches in the withdrawn position.

At the heart of the system is the activation device which is available in a 560 series 'push bar' design, the lower projection 570 series 'touch bar' design and the 580 series 'push pad' design. Each device can be used on its own to provide single point latching or with the addition of universal Pullman latches for multi-point latching.